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Longest Common Substring

Answered Longest Common Substring

  • Thursday, February 11, 2010 2:07 AM
     
     
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    Hi all,

    I need a LCS code with MPI. I have the code in C++, but don't know how to implement MPI in the code. Can someone help me?

    Thanks.


    Here is the code:

    #include <iostream>
    #include <string>

    using namespace std;
    int main () {
       
        string first, second, lcsub, max;
       
        cout << "Enter two words" << endl;
        cin >> first >> second;
            for (int i=0; i < first.length(); i++)
                for (int j=0; j < second.length(); j++)
                    for (int k=1; k <= first.length() && k <= second.length(); k++){
                        if (first.substr(i,k) == second.substr(j,k)){
                            lcsub = first.substr(i,k);
                        }
                        else{
                            if (lcsub.length() > max.length())
                                max=lcsub;
                            lcsub="";
                        }
                    }
                        if (lcsub.length() > max.length())
                                max=lcsub;
                            lcsub="";
                            cout << "Longest Common Substring: " << max << endl;
        return 0;
    }
     

All Replies

  • Thursday, February 11, 2010 9:14 PM
     
     Answered
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    Hi,

    The following may be interested to you for MPI programming.
    http://www.mcs.anl.gov/research/projects/mpi/usingmpi/

    It has rich MPI tutorial and good examples.

    Liwei
     
  • Friday, February 12, 2010 12:42 AM
     
      Has Code
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    Thanks a lot for the link, I have tutorials, but we learned only the basic things about MPI and I haven't enough knowledge to solve the problem :(. I have to finish the project until February 15, so if anyone can help me, I will be very glad.  

    I tried something but i don't know the next steps....

    #include <iostream>
#include <string>
#include "mpi.h"

using namespace std;

int main (int argc, char *argv[]) 
{
    MPI::Init(argc,argv);	
    
    int id,p;
    string first, second, lcsub, max;
    id = MPI::COMM_WORLD.Get_rank();
    p = MPI::COMM_WORLD.Get_size(); 
    
    cout << "Enter two words" << endl;
    cin >> first >> second;
        for (int i=0; i < first.length(); i++)
            for (int j=0; j < second.length(); j++)
                for (int k=1; k <= first.length() && k <second.length(); k++){
                    if (first.substr(i,k) == second.substr(j,k)){
                        lcsub = first.substr(i,k);
                    }
                    else{
                        if (lcsub.length() > max.length())
                            max=lcsub;
                        lcsub="";
                    }
                }
                    if (lcsub.length() > max.length())
                            max=lcsub;
                        lcsub="";
                        cout << "Longest Common Substring: " << max << endl;
    MPI::Finalize(); 
    return 0;
}
    I don't know how correct it is, and how to implement Send, Recieve or Broadcast functions...

    MPI_Bcast(max, max.length(), MPI::CHAR, root, MPI::COMM_WORLD);

    THANKS!